![Miklos Szeredi](/assets/img/avatar_default.png)
Michael Leun reported that running parallel opens on a fuse filesystem can trigger a "kernel BUG at mm/truncate.c:475" Gurudas Pai reported the same bug on NFS. The reason is, unmap_mapping_range() is not prepared for more than one concurrent invocation per inode. For example: thread1: going through a big range, stops in the middle of a vma and stores the restart address in vm_truncate_count. thread2: comes in with a small (e.g. single page) unmap request on the same vma, somewhere before restart_address, finds that the vma was already unmapped up to the restart address and happily returns without doing anything. Another scenario would be two big unmap requests, both having to restart the unmapping and each one setting vm_truncate_count to its own value. This could go on forever without any of them being able to finish. Truncate and hole punching already serialize with i_mutex. Other callers of unmap_mapping_range() do not, and it's difficult to get i_mutex protection for all callers. In particular ->d_revalidate(), which calls invalidate_inode_pages2_range() in fuse, may be called with or without i_mutex. This patch adds a new mutex to 'struct address_space' to prevent running multiple concurrent unmap_mapping_range() on the same mapping. [ We'll hopefully get rid of all this with the upcoming mm preemptibility series by Peter Zijlstra, the "mm: Remove i_mmap_mutex lockbreak" patch in particular. But that is for 2.6.39 ] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Reported-by: Michael Leun <lkml20101129@newton.leun.net> Reported-by: Gurudas Pai <gurudas.pai@oracle.com> Tested-by: Gurudas Pai <gurudas.pai@oracle.com> Acked-by: Hugh Dickins <hughd@google.com> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1733 lines
44 KiB
C
1733 lines
44 KiB
C
/*
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* linux/fs/inode.c
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*
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* (C) 1997 Linus Torvalds
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*/
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/dcache.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/writeback.h>
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#include <linux/module.h>
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#include <linux/backing-dev.h>
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#include <linux/wait.h>
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#include <linux/rwsem.h>
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#include <linux/hash.h>
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#include <linux/swap.h>
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#include <linux/security.h>
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#include <linux/pagemap.h>
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#include <linux/cdev.h>
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#include <linux/bootmem.h>
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#include <linux/fsnotify.h>
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#include <linux/mount.h>
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#include <linux/async.h>
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#include <linux/posix_acl.h>
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#include <linux/ima.h>
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/*
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* This is needed for the following functions:
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* - inode_has_buffers
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* - invalidate_bdev
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*
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* FIXME: remove all knowledge of the buffer layer from this file
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*/
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#include <linux/buffer_head.h>
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/*
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* New inode.c implementation.
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*
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* This implementation has the basic premise of trying
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* to be extremely low-overhead and SMP-safe, yet be
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* simple enough to be "obviously correct".
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*
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* Famous last words.
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*/
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/* inode dynamic allocation 1999, Andrea Arcangeli <andrea@suse.de> */
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/* #define INODE_PARANOIA 1 */
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/* #define INODE_DEBUG 1 */
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/*
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* Inode lookup is no longer as critical as it used to be:
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* most of the lookups are going to be through the dcache.
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*/
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#define I_HASHBITS i_hash_shift
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#define I_HASHMASK i_hash_mask
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static unsigned int i_hash_mask __read_mostly;
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static unsigned int i_hash_shift __read_mostly;
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/*
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* Each inode can be on two separate lists. One is
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* the hash list of the inode, used for lookups. The
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* other linked list is the "type" list:
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* "in_use" - valid inode, i_count > 0, i_nlink > 0
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* "dirty" - as "in_use" but also dirty
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* "unused" - valid inode, i_count = 0
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*
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* A "dirty" list is maintained for each super block,
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* allowing for low-overhead inode sync() operations.
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*/
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static LIST_HEAD(inode_lru);
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static struct hlist_head *inode_hashtable __read_mostly;
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/*
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* A simple spinlock to protect the list manipulations.
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*
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* NOTE! You also have to own the lock if you change
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* the i_state of an inode while it is in use..
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*/
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DEFINE_SPINLOCK(inode_lock);
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/*
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* iprune_sem provides exclusion between the kswapd or try_to_free_pages
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* icache shrinking path, and the umount path. Without this exclusion,
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* by the time prune_icache calls iput for the inode whose pages it has
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* been invalidating, or by the time it calls clear_inode & destroy_inode
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* from its final dispose_list, the struct super_block they refer to
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* (for inode->i_sb->s_op) may already have been freed and reused.
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*
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* We make this an rwsem because the fastpath is icache shrinking. In
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* some cases a filesystem may be doing a significant amount of work in
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* its inode reclaim code, so this should improve parallelism.
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*/
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static DECLARE_RWSEM(iprune_sem);
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/*
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* Statistics gathering..
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*/
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struct inodes_stat_t inodes_stat;
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static DEFINE_PER_CPU(unsigned int, nr_inodes);
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static struct kmem_cache *inode_cachep __read_mostly;
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static int get_nr_inodes(void)
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{
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int i;
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int sum = 0;
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for_each_possible_cpu(i)
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sum += per_cpu(nr_inodes, i);
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return sum < 0 ? 0 : sum;
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}
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static inline int get_nr_inodes_unused(void)
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{
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return inodes_stat.nr_unused;
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}
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int get_nr_dirty_inodes(void)
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{
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/* not actually dirty inodes, but a wild approximation */
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int nr_dirty = get_nr_inodes() - get_nr_inodes_unused();
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return nr_dirty > 0 ? nr_dirty : 0;
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}
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/*
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* Handle nr_inode sysctl
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*/
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#ifdef CONFIG_SYSCTL
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int proc_nr_inodes(ctl_table *table, int write,
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void __user *buffer, size_t *lenp, loff_t *ppos)
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{
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inodes_stat.nr_inodes = get_nr_inodes();
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return proc_dointvec(table, write, buffer, lenp, ppos);
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}
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#endif
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static void wake_up_inode(struct inode *inode)
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{
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/*
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* Prevent speculative execution through spin_unlock(&inode_lock);
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*/
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smp_mb();
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wake_up_bit(&inode->i_state, __I_NEW);
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}
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/**
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* inode_init_always - perform inode structure intialisation
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* @sb: superblock inode belongs to
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* @inode: inode to initialise
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*
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* These are initializations that need to be done on every inode
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* allocation as the fields are not initialised by slab allocation.
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*/
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int inode_init_always(struct super_block *sb, struct inode *inode)
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{
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static const struct address_space_operations empty_aops;
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static const struct inode_operations empty_iops;
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static const struct file_operations empty_fops;
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struct address_space *const mapping = &inode->i_data;
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inode->i_sb = sb;
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inode->i_blkbits = sb->s_blocksize_bits;
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inode->i_flags = 0;
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atomic_set(&inode->i_count, 1);
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inode->i_op = &empty_iops;
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inode->i_fop = &empty_fops;
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inode->i_nlink = 1;
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inode->i_uid = 0;
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inode->i_gid = 0;
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atomic_set(&inode->i_writecount, 0);
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inode->i_size = 0;
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inode->i_blocks = 0;
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inode->i_bytes = 0;
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inode->i_generation = 0;
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#ifdef CONFIG_QUOTA
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memset(&inode->i_dquot, 0, sizeof(inode->i_dquot));
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#endif
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inode->i_pipe = NULL;
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inode->i_bdev = NULL;
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inode->i_cdev = NULL;
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inode->i_rdev = 0;
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inode->dirtied_when = 0;
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if (security_inode_alloc(inode))
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goto out;
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spin_lock_init(&inode->i_lock);
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lockdep_set_class(&inode->i_lock, &sb->s_type->i_lock_key);
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mutex_init(&inode->i_mutex);
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lockdep_set_class(&inode->i_mutex, &sb->s_type->i_mutex_key);
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init_rwsem(&inode->i_alloc_sem);
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lockdep_set_class(&inode->i_alloc_sem, &sb->s_type->i_alloc_sem_key);
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mapping->a_ops = &empty_aops;
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mapping->host = inode;
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mapping->flags = 0;
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mapping_set_gfp_mask(mapping, GFP_HIGHUSER_MOVABLE);
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mapping->assoc_mapping = NULL;
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mapping->backing_dev_info = &default_backing_dev_info;
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mapping->writeback_index = 0;
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/*
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* If the block_device provides a backing_dev_info for client
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* inodes then use that. Otherwise the inode share the bdev's
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* backing_dev_info.
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*/
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if (sb->s_bdev) {
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struct backing_dev_info *bdi;
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bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
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mapping->backing_dev_info = bdi;
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}
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inode->i_private = NULL;
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inode->i_mapping = mapping;
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#ifdef CONFIG_FS_POSIX_ACL
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inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
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#endif
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#ifdef CONFIG_FSNOTIFY
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inode->i_fsnotify_mask = 0;
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#endif
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this_cpu_inc(nr_inodes);
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return 0;
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out:
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return -ENOMEM;
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}
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EXPORT_SYMBOL(inode_init_always);
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static struct inode *alloc_inode(struct super_block *sb)
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{
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struct inode *inode;
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if (sb->s_op->alloc_inode)
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inode = sb->s_op->alloc_inode(sb);
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else
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inode = kmem_cache_alloc(inode_cachep, GFP_KERNEL);
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if (!inode)
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return NULL;
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if (unlikely(inode_init_always(sb, inode))) {
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if (inode->i_sb->s_op->destroy_inode)
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inode->i_sb->s_op->destroy_inode(inode);
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else
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kmem_cache_free(inode_cachep, inode);
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return NULL;
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}
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return inode;
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}
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void free_inode_nonrcu(struct inode *inode)
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{
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kmem_cache_free(inode_cachep, inode);
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}
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EXPORT_SYMBOL(free_inode_nonrcu);
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void __destroy_inode(struct inode *inode)
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{
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BUG_ON(inode_has_buffers(inode));
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security_inode_free(inode);
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fsnotify_inode_delete(inode);
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#ifdef CONFIG_FS_POSIX_ACL
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if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
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posix_acl_release(inode->i_acl);
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if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
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posix_acl_release(inode->i_default_acl);
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#endif
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this_cpu_dec(nr_inodes);
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}
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EXPORT_SYMBOL(__destroy_inode);
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static void i_callback(struct rcu_head *head)
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{
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struct inode *inode = container_of(head, struct inode, i_rcu);
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INIT_LIST_HEAD(&inode->i_dentry);
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kmem_cache_free(inode_cachep, inode);
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}
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static void destroy_inode(struct inode *inode)
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{
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BUG_ON(!list_empty(&inode->i_lru));
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__destroy_inode(inode);
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if (inode->i_sb->s_op->destroy_inode)
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inode->i_sb->s_op->destroy_inode(inode);
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else
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call_rcu(&inode->i_rcu, i_callback);
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}
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void address_space_init_once(struct address_space *mapping)
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{
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memset(mapping, 0, sizeof(*mapping));
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INIT_RADIX_TREE(&mapping->page_tree, GFP_ATOMIC);
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spin_lock_init(&mapping->tree_lock);
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spin_lock_init(&mapping->i_mmap_lock);
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INIT_LIST_HEAD(&mapping->private_list);
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spin_lock_init(&mapping->private_lock);
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INIT_RAW_PRIO_TREE_ROOT(&mapping->i_mmap);
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INIT_LIST_HEAD(&mapping->i_mmap_nonlinear);
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mutex_init(&mapping->unmap_mutex);
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}
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EXPORT_SYMBOL(address_space_init_once);
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/*
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* These are initializations that only need to be done
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* once, because the fields are idempotent across use
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* of the inode, so let the slab aware of that.
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*/
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void inode_init_once(struct inode *inode)
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{
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memset(inode, 0, sizeof(*inode));
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INIT_HLIST_NODE(&inode->i_hash);
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INIT_LIST_HEAD(&inode->i_dentry);
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INIT_LIST_HEAD(&inode->i_devices);
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INIT_LIST_HEAD(&inode->i_wb_list);
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INIT_LIST_HEAD(&inode->i_lru);
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address_space_init_once(&inode->i_data);
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i_size_ordered_init(inode);
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#ifdef CONFIG_FSNOTIFY
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INIT_HLIST_HEAD(&inode->i_fsnotify_marks);
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#endif
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}
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EXPORT_SYMBOL(inode_init_once);
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static void init_once(void *foo)
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{
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struct inode *inode = (struct inode *) foo;
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inode_init_once(inode);
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}
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/*
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* inode_lock must be held
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*/
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void __iget(struct inode *inode)
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{
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atomic_inc(&inode->i_count);
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}
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/*
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* get additional reference to inode; caller must already hold one.
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*/
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void ihold(struct inode *inode)
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{
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WARN_ON(atomic_inc_return(&inode->i_count) < 2);
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}
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EXPORT_SYMBOL(ihold);
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static void inode_lru_list_add(struct inode *inode)
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{
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if (list_empty(&inode->i_lru)) {
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list_add(&inode->i_lru, &inode_lru);
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inodes_stat.nr_unused++;
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}
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}
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static void inode_lru_list_del(struct inode *inode)
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{
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if (!list_empty(&inode->i_lru)) {
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list_del_init(&inode->i_lru);
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inodes_stat.nr_unused--;
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}
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}
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static inline void __inode_sb_list_add(struct inode *inode)
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{
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list_add(&inode->i_sb_list, &inode->i_sb->s_inodes);
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}
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/**
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* inode_sb_list_add - add inode to the superblock list of inodes
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* @inode: inode to add
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*/
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void inode_sb_list_add(struct inode *inode)
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{
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spin_lock(&inode_lock);
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__inode_sb_list_add(inode);
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spin_unlock(&inode_lock);
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}
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EXPORT_SYMBOL_GPL(inode_sb_list_add);
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static inline void __inode_sb_list_del(struct inode *inode)
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{
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list_del_init(&inode->i_sb_list);
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}
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static unsigned long hash(struct super_block *sb, unsigned long hashval)
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{
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unsigned long tmp;
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tmp = (hashval * (unsigned long)sb) ^ (GOLDEN_RATIO_PRIME + hashval) /
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L1_CACHE_BYTES;
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tmp = tmp ^ ((tmp ^ GOLDEN_RATIO_PRIME) >> I_HASHBITS);
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return tmp & I_HASHMASK;
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}
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/**
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* __insert_inode_hash - hash an inode
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* @inode: unhashed inode
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* @hashval: unsigned long value used to locate this object in the
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* inode_hashtable.
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*
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* Add an inode to the inode hash for this superblock.
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*/
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void __insert_inode_hash(struct inode *inode, unsigned long hashval)
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{
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struct hlist_head *b = inode_hashtable + hash(inode->i_sb, hashval);
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spin_lock(&inode_lock);
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hlist_add_head(&inode->i_hash, b);
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spin_unlock(&inode_lock);
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}
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EXPORT_SYMBOL(__insert_inode_hash);
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/**
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* __remove_inode_hash - remove an inode from the hash
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* @inode: inode to unhash
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*
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* Remove an inode from the superblock.
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*/
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static void __remove_inode_hash(struct inode *inode)
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{
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hlist_del_init(&inode->i_hash);
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}
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/**
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* remove_inode_hash - remove an inode from the hash
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* @inode: inode to unhash
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*
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* Remove an inode from the superblock.
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*/
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void remove_inode_hash(struct inode *inode)
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{
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spin_lock(&inode_lock);
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hlist_del_init(&inode->i_hash);
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spin_unlock(&inode_lock);
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}
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EXPORT_SYMBOL(remove_inode_hash);
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void end_writeback(struct inode *inode)
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{
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might_sleep();
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BUG_ON(inode->i_data.nrpages);
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BUG_ON(!list_empty(&inode->i_data.private_list));
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BUG_ON(!(inode->i_state & I_FREEING));
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BUG_ON(inode->i_state & I_CLEAR);
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inode_sync_wait(inode);
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/* don't need i_lock here, no concurrent mods to i_state */
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inode->i_state = I_FREEING | I_CLEAR;
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}
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EXPORT_SYMBOL(end_writeback);
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static void evict(struct inode *inode)
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{
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const struct super_operations *op = inode->i_sb->s_op;
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if (op->evict_inode) {
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op->evict_inode(inode);
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} else {
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if (inode->i_data.nrpages)
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truncate_inode_pages(&inode->i_data, 0);
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end_writeback(inode);
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}
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if (S_ISBLK(inode->i_mode) && inode->i_bdev)
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bd_forget(inode);
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if (S_ISCHR(inode->i_mode) && inode->i_cdev)
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cd_forget(inode);
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}
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|
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/*
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* dispose_list - dispose of the contents of a local list
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* @head: the head of the list to free
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*
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* Dispose-list gets a local list with local inodes in it, so it doesn't
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* need to worry about list corruption and SMP locks.
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*/
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static void dispose_list(struct list_head *head)
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{
|
|
while (!list_empty(head)) {
|
|
struct inode *inode;
|
|
|
|
inode = list_first_entry(head, struct inode, i_lru);
|
|
list_del_init(&inode->i_lru);
|
|
|
|
evict(inode);
|
|
|
|
spin_lock(&inode_lock);
|
|
__remove_inode_hash(inode);
|
|
__inode_sb_list_del(inode);
|
|
spin_unlock(&inode_lock);
|
|
|
|
wake_up_inode(inode);
|
|
destroy_inode(inode);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* evict_inodes - evict all evictable inodes for a superblock
|
|
* @sb: superblock to operate on
|
|
*
|
|
* Make sure that no inodes with zero refcount are retained. This is
|
|
* called by superblock shutdown after having MS_ACTIVE flag removed,
|
|
* so any inode reaching zero refcount during or after that call will
|
|
* be immediately evicted.
|
|
*/
|
|
void evict_inodes(struct super_block *sb)
|
|
{
|
|
struct inode *inode, *next;
|
|
LIST_HEAD(dispose);
|
|
|
|
down_write(&iprune_sem);
|
|
|
|
spin_lock(&inode_lock);
|
|
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
|
|
if (atomic_read(&inode->i_count))
|
|
continue;
|
|
|
|
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE)) {
|
|
WARN_ON(1);
|
|
continue;
|
|
}
|
|
|
|
inode->i_state |= I_FREEING;
|
|
|
|
/*
|
|
* Move the inode off the IO lists and LRU once I_FREEING is
|
|
* set so that it won't get moved back on there if it is dirty.
|
|
*/
|
|
list_move(&inode->i_lru, &dispose);
|
|
list_del_init(&inode->i_wb_list);
|
|
if (!(inode->i_state & (I_DIRTY | I_SYNC)))
|
|
inodes_stat.nr_unused--;
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
|
|
dispose_list(&dispose);
|
|
up_write(&iprune_sem);
|
|
}
|
|
|
|
/**
|
|
* invalidate_inodes - attempt to free all inodes on a superblock
|
|
* @sb: superblock to operate on
|
|
*
|
|
* Attempts to free all inodes for a given superblock. If there were any
|
|
* busy inodes return a non-zero value, else zero.
|
|
*/
|
|
int invalidate_inodes(struct super_block *sb)
|
|
{
|
|
int busy = 0;
|
|
struct inode *inode, *next;
|
|
LIST_HEAD(dispose);
|
|
|
|
down_write(&iprune_sem);
|
|
|
|
spin_lock(&inode_lock);
|
|
list_for_each_entry_safe(inode, next, &sb->s_inodes, i_sb_list) {
|
|
if (inode->i_state & (I_NEW | I_FREEING | I_WILL_FREE))
|
|
continue;
|
|
if (atomic_read(&inode->i_count)) {
|
|
busy = 1;
|
|
continue;
|
|
}
|
|
|
|
inode->i_state |= I_FREEING;
|
|
|
|
/*
|
|
* Move the inode off the IO lists and LRU once I_FREEING is
|
|
* set so that it won't get moved back on there if it is dirty.
|
|
*/
|
|
list_move(&inode->i_lru, &dispose);
|
|
list_del_init(&inode->i_wb_list);
|
|
if (!(inode->i_state & (I_DIRTY | I_SYNC)))
|
|
inodes_stat.nr_unused--;
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
|
|
dispose_list(&dispose);
|
|
up_write(&iprune_sem);
|
|
|
|
return busy;
|
|
}
|
|
|
|
static int can_unuse(struct inode *inode)
|
|
{
|
|
if (inode->i_state & ~I_REFERENCED)
|
|
return 0;
|
|
if (inode_has_buffers(inode))
|
|
return 0;
|
|
if (atomic_read(&inode->i_count))
|
|
return 0;
|
|
if (inode->i_data.nrpages)
|
|
return 0;
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* Scan `goal' inodes on the unused list for freeable ones. They are moved to a
|
|
* temporary list and then are freed outside inode_lock by dispose_list().
|
|
*
|
|
* Any inodes which are pinned purely because of attached pagecache have their
|
|
* pagecache removed. If the inode has metadata buffers attached to
|
|
* mapping->private_list then try to remove them.
|
|
*
|
|
* If the inode has the I_REFERENCED flag set, then it means that it has been
|
|
* used recently - the flag is set in iput_final(). When we encounter such an
|
|
* inode, clear the flag and move it to the back of the LRU so it gets another
|
|
* pass through the LRU before it gets reclaimed. This is necessary because of
|
|
* the fact we are doing lazy LRU updates to minimise lock contention so the
|
|
* LRU does not have strict ordering. Hence we don't want to reclaim inodes
|
|
* with this flag set because they are the inodes that are out of order.
|
|
*/
|
|
static void prune_icache(int nr_to_scan)
|
|
{
|
|
LIST_HEAD(freeable);
|
|
int nr_scanned;
|
|
unsigned long reap = 0;
|
|
|
|
down_read(&iprune_sem);
|
|
spin_lock(&inode_lock);
|
|
for (nr_scanned = 0; nr_scanned < nr_to_scan; nr_scanned++) {
|
|
struct inode *inode;
|
|
|
|
if (list_empty(&inode_lru))
|
|
break;
|
|
|
|
inode = list_entry(inode_lru.prev, struct inode, i_lru);
|
|
|
|
/*
|
|
* Referenced or dirty inodes are still in use. Give them
|
|
* another pass through the LRU as we canot reclaim them now.
|
|
*/
|
|
if (atomic_read(&inode->i_count) ||
|
|
(inode->i_state & ~I_REFERENCED)) {
|
|
list_del_init(&inode->i_lru);
|
|
inodes_stat.nr_unused--;
|
|
continue;
|
|
}
|
|
|
|
/* recently referenced inodes get one more pass */
|
|
if (inode->i_state & I_REFERENCED) {
|
|
list_move(&inode->i_lru, &inode_lru);
|
|
inode->i_state &= ~I_REFERENCED;
|
|
continue;
|
|
}
|
|
if (inode_has_buffers(inode) || inode->i_data.nrpages) {
|
|
__iget(inode);
|
|
spin_unlock(&inode_lock);
|
|
if (remove_inode_buffers(inode))
|
|
reap += invalidate_mapping_pages(&inode->i_data,
|
|
0, -1);
|
|
iput(inode);
|
|
spin_lock(&inode_lock);
|
|
|
|
if (inode != list_entry(inode_lru.next,
|
|
struct inode, i_lru))
|
|
continue; /* wrong inode or list_empty */
|
|
if (!can_unuse(inode))
|
|
continue;
|
|
}
|
|
WARN_ON(inode->i_state & I_NEW);
|
|
inode->i_state |= I_FREEING;
|
|
|
|
/*
|
|
* Move the inode off the IO lists and LRU once I_FREEING is
|
|
* set so that it won't get moved back on there if it is dirty.
|
|
*/
|
|
list_move(&inode->i_lru, &freeable);
|
|
list_del_init(&inode->i_wb_list);
|
|
inodes_stat.nr_unused--;
|
|
}
|
|
if (current_is_kswapd())
|
|
__count_vm_events(KSWAPD_INODESTEAL, reap);
|
|
else
|
|
__count_vm_events(PGINODESTEAL, reap);
|
|
spin_unlock(&inode_lock);
|
|
|
|
dispose_list(&freeable);
|
|
up_read(&iprune_sem);
|
|
}
|
|
|
|
/*
|
|
* shrink_icache_memory() will attempt to reclaim some unused inodes. Here,
|
|
* "unused" means that no dentries are referring to the inodes: the files are
|
|
* not open and the dcache references to those inodes have already been
|
|
* reclaimed.
|
|
*
|
|
* This function is passed the number of inodes to scan, and it returns the
|
|
* total number of remaining possibly-reclaimable inodes.
|
|
*/
|
|
static int shrink_icache_memory(struct shrinker *shrink, int nr, gfp_t gfp_mask)
|
|
{
|
|
if (nr) {
|
|
/*
|
|
* Nasty deadlock avoidance. We may hold various FS locks,
|
|
* and we don't want to recurse into the FS that called us
|
|
* in clear_inode() and friends..
|
|
*/
|
|
if (!(gfp_mask & __GFP_FS))
|
|
return -1;
|
|
prune_icache(nr);
|
|
}
|
|
return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure;
|
|
}
|
|
|
|
static struct shrinker icache_shrinker = {
|
|
.shrink = shrink_icache_memory,
|
|
.seeks = DEFAULT_SEEKS,
|
|
};
|
|
|
|
static void __wait_on_freeing_inode(struct inode *inode);
|
|
/*
|
|
* Called with the inode lock held.
|
|
*/
|
|
static struct inode *find_inode(struct super_block *sb,
|
|
struct hlist_head *head,
|
|
int (*test)(struct inode *, void *),
|
|
void *data)
|
|
{
|
|
struct hlist_node *node;
|
|
struct inode *inode = NULL;
|
|
|
|
repeat:
|
|
hlist_for_each_entry(inode, node, head, i_hash) {
|
|
if (inode->i_sb != sb)
|
|
continue;
|
|
if (!test(inode, data))
|
|
continue;
|
|
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
|
|
__wait_on_freeing_inode(inode);
|
|
goto repeat;
|
|
}
|
|
__iget(inode);
|
|
return inode;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* find_inode_fast is the fast path version of find_inode, see the comment at
|
|
* iget_locked for details.
|
|
*/
|
|
static struct inode *find_inode_fast(struct super_block *sb,
|
|
struct hlist_head *head, unsigned long ino)
|
|
{
|
|
struct hlist_node *node;
|
|
struct inode *inode = NULL;
|
|
|
|
repeat:
|
|
hlist_for_each_entry(inode, node, head, i_hash) {
|
|
if (inode->i_ino != ino)
|
|
continue;
|
|
if (inode->i_sb != sb)
|
|
continue;
|
|
if (inode->i_state & (I_FREEING|I_WILL_FREE)) {
|
|
__wait_on_freeing_inode(inode);
|
|
goto repeat;
|
|
}
|
|
__iget(inode);
|
|
return inode;
|
|
}
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Each cpu owns a range of LAST_INO_BATCH numbers.
|
|
* 'shared_last_ino' is dirtied only once out of LAST_INO_BATCH allocations,
|
|
* to renew the exhausted range.
|
|
*
|
|
* This does not significantly increase overflow rate because every CPU can
|
|
* consume at most LAST_INO_BATCH-1 unused inode numbers. So there is
|
|
* NR_CPUS*(LAST_INO_BATCH-1) wastage. At 4096 and 1024, this is ~0.1% of the
|
|
* 2^32 range, and is a worst-case. Even a 50% wastage would only increase
|
|
* overflow rate by 2x, which does not seem too significant.
|
|
*
|
|
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
|
|
* error if st_ino won't fit in target struct field. Use 32bit counter
|
|
* here to attempt to avoid that.
|
|
*/
|
|
#define LAST_INO_BATCH 1024
|
|
static DEFINE_PER_CPU(unsigned int, last_ino);
|
|
|
|
unsigned int get_next_ino(void)
|
|
{
|
|
unsigned int *p = &get_cpu_var(last_ino);
|
|
unsigned int res = *p;
|
|
|
|
#ifdef CONFIG_SMP
|
|
if (unlikely((res & (LAST_INO_BATCH-1)) == 0)) {
|
|
static atomic_t shared_last_ino;
|
|
int next = atomic_add_return(LAST_INO_BATCH, &shared_last_ino);
|
|
|
|
res = next - LAST_INO_BATCH;
|
|
}
|
|
#endif
|
|
|
|
*p = ++res;
|
|
put_cpu_var(last_ino);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(get_next_ino);
|
|
|
|
/**
|
|
* new_inode - obtain an inode
|
|
* @sb: superblock
|
|
*
|
|
* Allocates a new inode for given superblock. The default gfp_mask
|
|
* for allocations related to inode->i_mapping is GFP_HIGHUSER_MOVABLE.
|
|
* If HIGHMEM pages are unsuitable or it is known that pages allocated
|
|
* for the page cache are not reclaimable or migratable,
|
|
* mapping_set_gfp_mask() must be called with suitable flags on the
|
|
* newly created inode's mapping
|
|
*
|
|
*/
|
|
struct inode *new_inode(struct super_block *sb)
|
|
{
|
|
struct inode *inode;
|
|
|
|
spin_lock_prefetch(&inode_lock);
|
|
|
|
inode = alloc_inode(sb);
|
|
if (inode) {
|
|
spin_lock(&inode_lock);
|
|
__inode_sb_list_add(inode);
|
|
inode->i_state = 0;
|
|
spin_unlock(&inode_lock);
|
|
}
|
|
return inode;
|
|
}
|
|
EXPORT_SYMBOL(new_inode);
|
|
|
|
void unlock_new_inode(struct inode *inode)
|
|
{
|
|
#ifdef CONFIG_DEBUG_LOCK_ALLOC
|
|
if (S_ISDIR(inode->i_mode)) {
|
|
struct file_system_type *type = inode->i_sb->s_type;
|
|
|
|
/* Set new key only if filesystem hasn't already changed it */
|
|
if (!lockdep_match_class(&inode->i_mutex,
|
|
&type->i_mutex_key)) {
|
|
/*
|
|
* ensure nobody is actually holding i_mutex
|
|
*/
|
|
mutex_destroy(&inode->i_mutex);
|
|
mutex_init(&inode->i_mutex);
|
|
lockdep_set_class(&inode->i_mutex,
|
|
&type->i_mutex_dir_key);
|
|
}
|
|
}
|
|
#endif
|
|
/*
|
|
* This is special! We do not need the spinlock when clearing I_NEW,
|
|
* because we're guaranteed that nobody else tries to do anything about
|
|
* the state of the inode when it is locked, as we just created it (so
|
|
* there can be no old holders that haven't tested I_NEW).
|
|
* However we must emit the memory barrier so that other CPUs reliably
|
|
* see the clearing of I_NEW after the other inode initialisation has
|
|
* completed.
|
|
*/
|
|
smp_mb();
|
|
WARN_ON(!(inode->i_state & I_NEW));
|
|
inode->i_state &= ~I_NEW;
|
|
wake_up_inode(inode);
|
|
}
|
|
EXPORT_SYMBOL(unlock_new_inode);
|
|
|
|
/*
|
|
* This is called without the inode lock held.. Be careful.
|
|
*
|
|
* We no longer cache the sb_flags in i_flags - see fs.h
|
|
* -- rmk@arm.uk.linux.org
|
|
*/
|
|
static struct inode *get_new_inode(struct super_block *sb,
|
|
struct hlist_head *head,
|
|
int (*test)(struct inode *, void *),
|
|
int (*set)(struct inode *, void *),
|
|
void *data)
|
|
{
|
|
struct inode *inode;
|
|
|
|
inode = alloc_inode(sb);
|
|
if (inode) {
|
|
struct inode *old;
|
|
|
|
spin_lock(&inode_lock);
|
|
/* We released the lock, so.. */
|
|
old = find_inode(sb, head, test, data);
|
|
if (!old) {
|
|
if (set(inode, data))
|
|
goto set_failed;
|
|
|
|
hlist_add_head(&inode->i_hash, head);
|
|
__inode_sb_list_add(inode);
|
|
inode->i_state = I_NEW;
|
|
spin_unlock(&inode_lock);
|
|
|
|
/* Return the locked inode with I_NEW set, the
|
|
* caller is responsible for filling in the contents
|
|
*/
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* Uhhuh, somebody else created the same inode under
|
|
* us. Use the old inode instead of the one we just
|
|
* allocated.
|
|
*/
|
|
spin_unlock(&inode_lock);
|
|
destroy_inode(inode);
|
|
inode = old;
|
|
wait_on_inode(inode);
|
|
}
|
|
return inode;
|
|
|
|
set_failed:
|
|
spin_unlock(&inode_lock);
|
|
destroy_inode(inode);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* get_new_inode_fast is the fast path version of get_new_inode, see the
|
|
* comment at iget_locked for details.
|
|
*/
|
|
static struct inode *get_new_inode_fast(struct super_block *sb,
|
|
struct hlist_head *head, unsigned long ino)
|
|
{
|
|
struct inode *inode;
|
|
|
|
inode = alloc_inode(sb);
|
|
if (inode) {
|
|
struct inode *old;
|
|
|
|
spin_lock(&inode_lock);
|
|
/* We released the lock, so.. */
|
|
old = find_inode_fast(sb, head, ino);
|
|
if (!old) {
|
|
inode->i_ino = ino;
|
|
hlist_add_head(&inode->i_hash, head);
|
|
__inode_sb_list_add(inode);
|
|
inode->i_state = I_NEW;
|
|
spin_unlock(&inode_lock);
|
|
|
|
/* Return the locked inode with I_NEW set, the
|
|
* caller is responsible for filling in the contents
|
|
*/
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* Uhhuh, somebody else created the same inode under
|
|
* us. Use the old inode instead of the one we just
|
|
* allocated.
|
|
*/
|
|
spin_unlock(&inode_lock);
|
|
destroy_inode(inode);
|
|
inode = old;
|
|
wait_on_inode(inode);
|
|
}
|
|
return inode;
|
|
}
|
|
|
|
/*
|
|
* search the inode cache for a matching inode number.
|
|
* If we find one, then the inode number we are trying to
|
|
* allocate is not unique and so we should not use it.
|
|
*
|
|
* Returns 1 if the inode number is unique, 0 if it is not.
|
|
*/
|
|
static int test_inode_iunique(struct super_block *sb, unsigned long ino)
|
|
{
|
|
struct hlist_head *b = inode_hashtable + hash(sb, ino);
|
|
struct hlist_node *node;
|
|
struct inode *inode;
|
|
|
|
hlist_for_each_entry(inode, node, b, i_hash) {
|
|
if (inode->i_ino == ino && inode->i_sb == sb)
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/**
|
|
* iunique - get a unique inode number
|
|
* @sb: superblock
|
|
* @max_reserved: highest reserved inode number
|
|
*
|
|
* Obtain an inode number that is unique on the system for a given
|
|
* superblock. This is used by file systems that have no natural
|
|
* permanent inode numbering system. An inode number is returned that
|
|
* is higher than the reserved limit but unique.
|
|
*
|
|
* BUGS:
|
|
* With a large number of inodes live on the file system this function
|
|
* currently becomes quite slow.
|
|
*/
|
|
ino_t iunique(struct super_block *sb, ino_t max_reserved)
|
|
{
|
|
/*
|
|
* On a 32bit, non LFS stat() call, glibc will generate an EOVERFLOW
|
|
* error if st_ino won't fit in target struct field. Use 32bit counter
|
|
* here to attempt to avoid that.
|
|
*/
|
|
static DEFINE_SPINLOCK(iunique_lock);
|
|
static unsigned int counter;
|
|
ino_t res;
|
|
|
|
spin_lock(&inode_lock);
|
|
spin_lock(&iunique_lock);
|
|
do {
|
|
if (counter <= max_reserved)
|
|
counter = max_reserved + 1;
|
|
res = counter++;
|
|
} while (!test_inode_iunique(sb, res));
|
|
spin_unlock(&iunique_lock);
|
|
spin_unlock(&inode_lock);
|
|
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(iunique);
|
|
|
|
struct inode *igrab(struct inode *inode)
|
|
{
|
|
spin_lock(&inode_lock);
|
|
if (!(inode->i_state & (I_FREEING|I_WILL_FREE)))
|
|
__iget(inode);
|
|
else
|
|
/*
|
|
* Handle the case where s_op->clear_inode is not been
|
|
* called yet, and somebody is calling igrab
|
|
* while the inode is getting freed.
|
|
*/
|
|
inode = NULL;
|
|
spin_unlock(&inode_lock);
|
|
return inode;
|
|
}
|
|
EXPORT_SYMBOL(igrab);
|
|
|
|
/**
|
|
* ifind - internal function, you want ilookup5() or iget5().
|
|
* @sb: super block of file system to search
|
|
* @head: the head of the list to search
|
|
* @test: callback used for comparisons between inodes
|
|
* @data: opaque data pointer to pass to @test
|
|
* @wait: if true wait for the inode to be unlocked, if false do not
|
|
*
|
|
* ifind() searches for the inode specified by @data in the inode
|
|
* cache. This is a generalized version of ifind_fast() for file systems where
|
|
* the inode number is not sufficient for unique identification of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*
|
|
* Note, @test is called with the inode_lock held, so can't sleep.
|
|
*/
|
|
static struct inode *ifind(struct super_block *sb,
|
|
struct hlist_head *head, int (*test)(struct inode *, void *),
|
|
void *data, const int wait)
|
|
{
|
|
struct inode *inode;
|
|
|
|
spin_lock(&inode_lock);
|
|
inode = find_inode(sb, head, test, data);
|
|
if (inode) {
|
|
spin_unlock(&inode_lock);
|
|
if (likely(wait))
|
|
wait_on_inode(inode);
|
|
return inode;
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* ifind_fast - internal function, you want ilookup() or iget().
|
|
* @sb: super block of file system to search
|
|
* @head: head of the list to search
|
|
* @ino: inode number to search for
|
|
*
|
|
* ifind_fast() searches for the inode @ino in the inode cache. This is for
|
|
* file systems where the inode number is sufficient for unique identification
|
|
* of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*/
|
|
static struct inode *ifind_fast(struct super_block *sb,
|
|
struct hlist_head *head, unsigned long ino)
|
|
{
|
|
struct inode *inode;
|
|
|
|
spin_lock(&inode_lock);
|
|
inode = find_inode_fast(sb, head, ino);
|
|
if (inode) {
|
|
spin_unlock(&inode_lock);
|
|
wait_on_inode(inode);
|
|
return inode;
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
return NULL;
|
|
}
|
|
|
|
/**
|
|
* ilookup5_nowait - search for an inode in the inode cache
|
|
* @sb: super block of file system to search
|
|
* @hashval: hash value (usually inode number) to search for
|
|
* @test: callback used for comparisons between inodes
|
|
* @data: opaque data pointer to pass to @test
|
|
*
|
|
* ilookup5() uses ifind() to search for the inode specified by @hashval and
|
|
* @data in the inode cache. This is a generalized version of ilookup() for
|
|
* file systems where the inode number is not sufficient for unique
|
|
* identification of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count. Note, the inode lock is not waited upon so you have to be
|
|
* very careful what you do with the returned inode. You probably should be
|
|
* using ilookup5() instead.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*
|
|
* Note, @test is called with the inode_lock held, so can't sleep.
|
|
*/
|
|
struct inode *ilookup5_nowait(struct super_block *sb, unsigned long hashval,
|
|
int (*test)(struct inode *, void *), void *data)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
|
|
|
|
return ifind(sb, head, test, data, 0);
|
|
}
|
|
EXPORT_SYMBOL(ilookup5_nowait);
|
|
|
|
/**
|
|
* ilookup5 - search for an inode in the inode cache
|
|
* @sb: super block of file system to search
|
|
* @hashval: hash value (usually inode number) to search for
|
|
* @test: callback used for comparisons between inodes
|
|
* @data: opaque data pointer to pass to @test
|
|
*
|
|
* ilookup5() uses ifind() to search for the inode specified by @hashval and
|
|
* @data in the inode cache. This is a generalized version of ilookup() for
|
|
* file systems where the inode number is not sufficient for unique
|
|
* identification of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode lock is waited upon and the inode is
|
|
* returned with an incremented reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*
|
|
* Note, @test is called with the inode_lock held, so can't sleep.
|
|
*/
|
|
struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
|
|
int (*test)(struct inode *, void *), void *data)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
|
|
|
|
return ifind(sb, head, test, data, 1);
|
|
}
|
|
EXPORT_SYMBOL(ilookup5);
|
|
|
|
/**
|
|
* ilookup - search for an inode in the inode cache
|
|
* @sb: super block of file system to search
|
|
* @ino: inode number to search for
|
|
*
|
|
* ilookup() uses ifind_fast() to search for the inode @ino in the inode cache.
|
|
* This is for file systems where the inode number is sufficient for unique
|
|
* identification of an inode.
|
|
*
|
|
* If the inode is in the cache, the inode is returned with an incremented
|
|
* reference count.
|
|
*
|
|
* Otherwise NULL is returned.
|
|
*/
|
|
struct inode *ilookup(struct super_block *sb, unsigned long ino)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, ino);
|
|
|
|
return ifind_fast(sb, head, ino);
|
|
}
|
|
EXPORT_SYMBOL(ilookup);
|
|
|
|
/**
|
|
* iget5_locked - obtain an inode from a mounted file system
|
|
* @sb: super block of file system
|
|
* @hashval: hash value (usually inode number) to get
|
|
* @test: callback used for comparisons between inodes
|
|
* @set: callback used to initialize a new struct inode
|
|
* @data: opaque data pointer to pass to @test and @set
|
|
*
|
|
* iget5_locked() uses ifind() to search for the inode specified by @hashval
|
|
* and @data in the inode cache and if present it is returned with an increased
|
|
* reference count. This is a generalized version of iget_locked() for file
|
|
* systems where the inode number is not sufficient for unique identification
|
|
* of an inode.
|
|
*
|
|
* If the inode is not in cache, get_new_inode() is called to allocate a new
|
|
* inode and this is returned locked, hashed, and with the I_NEW flag set. The
|
|
* file system gets to fill it in before unlocking it via unlock_new_inode().
|
|
*
|
|
* Note both @test and @set are called with the inode_lock held, so can't sleep.
|
|
*/
|
|
struct inode *iget5_locked(struct super_block *sb, unsigned long hashval,
|
|
int (*test)(struct inode *, void *),
|
|
int (*set)(struct inode *, void *), void *data)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
|
|
struct inode *inode;
|
|
|
|
inode = ifind(sb, head, test, data, 1);
|
|
if (inode)
|
|
return inode;
|
|
/*
|
|
* get_new_inode() will do the right thing, re-trying the search
|
|
* in case it had to block at any point.
|
|
*/
|
|
return get_new_inode(sb, head, test, set, data);
|
|
}
|
|
EXPORT_SYMBOL(iget5_locked);
|
|
|
|
/**
|
|
* iget_locked - obtain an inode from a mounted file system
|
|
* @sb: super block of file system
|
|
* @ino: inode number to get
|
|
*
|
|
* iget_locked() uses ifind_fast() to search for the inode specified by @ino in
|
|
* the inode cache and if present it is returned with an increased reference
|
|
* count. This is for file systems where the inode number is sufficient for
|
|
* unique identification of an inode.
|
|
*
|
|
* If the inode is not in cache, get_new_inode_fast() is called to allocate a
|
|
* new inode and this is returned locked, hashed, and with the I_NEW flag set.
|
|
* The file system gets to fill it in before unlocking it via
|
|
* unlock_new_inode().
|
|
*/
|
|
struct inode *iget_locked(struct super_block *sb, unsigned long ino)
|
|
{
|
|
struct hlist_head *head = inode_hashtable + hash(sb, ino);
|
|
struct inode *inode;
|
|
|
|
inode = ifind_fast(sb, head, ino);
|
|
if (inode)
|
|
return inode;
|
|
/*
|
|
* get_new_inode_fast() will do the right thing, re-trying the search
|
|
* in case it had to block at any point.
|
|
*/
|
|
return get_new_inode_fast(sb, head, ino);
|
|
}
|
|
EXPORT_SYMBOL(iget_locked);
|
|
|
|
int insert_inode_locked(struct inode *inode)
|
|
{
|
|
struct super_block *sb = inode->i_sb;
|
|
ino_t ino = inode->i_ino;
|
|
struct hlist_head *head = inode_hashtable + hash(sb, ino);
|
|
|
|
inode->i_state |= I_NEW;
|
|
while (1) {
|
|
struct hlist_node *node;
|
|
struct inode *old = NULL;
|
|
spin_lock(&inode_lock);
|
|
hlist_for_each_entry(old, node, head, i_hash) {
|
|
if (old->i_ino != ino)
|
|
continue;
|
|
if (old->i_sb != sb)
|
|
continue;
|
|
if (old->i_state & (I_FREEING|I_WILL_FREE))
|
|
continue;
|
|
break;
|
|
}
|
|
if (likely(!node)) {
|
|
hlist_add_head(&inode->i_hash, head);
|
|
spin_unlock(&inode_lock);
|
|
return 0;
|
|
}
|
|
__iget(old);
|
|
spin_unlock(&inode_lock);
|
|
wait_on_inode(old);
|
|
if (unlikely(!inode_unhashed(old))) {
|
|
iput(old);
|
|
return -EBUSY;
|
|
}
|
|
iput(old);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(insert_inode_locked);
|
|
|
|
int insert_inode_locked4(struct inode *inode, unsigned long hashval,
|
|
int (*test)(struct inode *, void *), void *data)
|
|
{
|
|
struct super_block *sb = inode->i_sb;
|
|
struct hlist_head *head = inode_hashtable + hash(sb, hashval);
|
|
|
|
inode->i_state |= I_NEW;
|
|
|
|
while (1) {
|
|
struct hlist_node *node;
|
|
struct inode *old = NULL;
|
|
|
|
spin_lock(&inode_lock);
|
|
hlist_for_each_entry(old, node, head, i_hash) {
|
|
if (old->i_sb != sb)
|
|
continue;
|
|
if (!test(old, data))
|
|
continue;
|
|
if (old->i_state & (I_FREEING|I_WILL_FREE))
|
|
continue;
|
|
break;
|
|
}
|
|
if (likely(!node)) {
|
|
hlist_add_head(&inode->i_hash, head);
|
|
spin_unlock(&inode_lock);
|
|
return 0;
|
|
}
|
|
__iget(old);
|
|
spin_unlock(&inode_lock);
|
|
wait_on_inode(old);
|
|
if (unlikely(!inode_unhashed(old))) {
|
|
iput(old);
|
|
return -EBUSY;
|
|
}
|
|
iput(old);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(insert_inode_locked4);
|
|
|
|
|
|
int generic_delete_inode(struct inode *inode)
|
|
{
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(generic_delete_inode);
|
|
|
|
/*
|
|
* Normal UNIX filesystem behaviour: delete the
|
|
* inode when the usage count drops to zero, and
|
|
* i_nlink is zero.
|
|
*/
|
|
int generic_drop_inode(struct inode *inode)
|
|
{
|
|
return !inode->i_nlink || inode_unhashed(inode);
|
|
}
|
|
EXPORT_SYMBOL_GPL(generic_drop_inode);
|
|
|
|
/*
|
|
* Called when we're dropping the last reference
|
|
* to an inode.
|
|
*
|
|
* Call the FS "drop_inode()" function, defaulting to
|
|
* the legacy UNIX filesystem behaviour. If it tells
|
|
* us to evict inode, do so. Otherwise, retain inode
|
|
* in cache if fs is alive, sync and evict if fs is
|
|
* shutting down.
|
|
*/
|
|
static void iput_final(struct inode *inode)
|
|
{
|
|
struct super_block *sb = inode->i_sb;
|
|
const struct super_operations *op = inode->i_sb->s_op;
|
|
int drop;
|
|
|
|
if (op && op->drop_inode)
|
|
drop = op->drop_inode(inode);
|
|
else
|
|
drop = generic_drop_inode(inode);
|
|
|
|
if (!drop) {
|
|
if (sb->s_flags & MS_ACTIVE) {
|
|
inode->i_state |= I_REFERENCED;
|
|
if (!(inode->i_state & (I_DIRTY|I_SYNC))) {
|
|
inode_lru_list_add(inode);
|
|
}
|
|
spin_unlock(&inode_lock);
|
|
return;
|
|
}
|
|
WARN_ON(inode->i_state & I_NEW);
|
|
inode->i_state |= I_WILL_FREE;
|
|
spin_unlock(&inode_lock);
|
|
write_inode_now(inode, 1);
|
|
spin_lock(&inode_lock);
|
|
WARN_ON(inode->i_state & I_NEW);
|
|
inode->i_state &= ~I_WILL_FREE;
|
|
__remove_inode_hash(inode);
|
|
}
|
|
|
|
WARN_ON(inode->i_state & I_NEW);
|
|
inode->i_state |= I_FREEING;
|
|
|
|
/*
|
|
* Move the inode off the IO lists and LRU once I_FREEING is
|
|
* set so that it won't get moved back on there if it is dirty.
|
|
*/
|
|
inode_lru_list_del(inode);
|
|
list_del_init(&inode->i_wb_list);
|
|
|
|
__inode_sb_list_del(inode);
|
|
spin_unlock(&inode_lock);
|
|
evict(inode);
|
|
remove_inode_hash(inode);
|
|
wake_up_inode(inode);
|
|
BUG_ON(inode->i_state != (I_FREEING | I_CLEAR));
|
|
destroy_inode(inode);
|
|
}
|
|
|
|
/**
|
|
* iput - put an inode
|
|
* @inode: inode to put
|
|
*
|
|
* Puts an inode, dropping its usage count. If the inode use count hits
|
|
* zero, the inode is then freed and may also be destroyed.
|
|
*
|
|
* Consequently, iput() can sleep.
|
|
*/
|
|
void iput(struct inode *inode)
|
|
{
|
|
if (inode) {
|
|
BUG_ON(inode->i_state & I_CLEAR);
|
|
|
|
if (atomic_dec_and_lock(&inode->i_count, &inode_lock))
|
|
iput_final(inode);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(iput);
|
|
|
|
/**
|
|
* bmap - find a block number in a file
|
|
* @inode: inode of file
|
|
* @block: block to find
|
|
*
|
|
* Returns the block number on the device holding the inode that
|
|
* is the disk block number for the block of the file requested.
|
|
* That is, asked for block 4 of inode 1 the function will return the
|
|
* disk block relative to the disk start that holds that block of the
|
|
* file.
|
|
*/
|
|
sector_t bmap(struct inode *inode, sector_t block)
|
|
{
|
|
sector_t res = 0;
|
|
if (inode->i_mapping->a_ops->bmap)
|
|
res = inode->i_mapping->a_ops->bmap(inode->i_mapping, block);
|
|
return res;
|
|
}
|
|
EXPORT_SYMBOL(bmap);
|
|
|
|
/*
|
|
* With relative atime, only update atime if the previous atime is
|
|
* earlier than either the ctime or mtime or if at least a day has
|
|
* passed since the last atime update.
|
|
*/
|
|
static int relatime_need_update(struct vfsmount *mnt, struct inode *inode,
|
|
struct timespec now)
|
|
{
|
|
|
|
if (!(mnt->mnt_flags & MNT_RELATIME))
|
|
return 1;
|
|
/*
|
|
* Is mtime younger than atime? If yes, update atime:
|
|
*/
|
|
if (timespec_compare(&inode->i_mtime, &inode->i_atime) >= 0)
|
|
return 1;
|
|
/*
|
|
* Is ctime younger than atime? If yes, update atime:
|
|
*/
|
|
if (timespec_compare(&inode->i_ctime, &inode->i_atime) >= 0)
|
|
return 1;
|
|
|
|
/*
|
|
* Is the previous atime value older than a day? If yes,
|
|
* update atime:
|
|
*/
|
|
if ((long)(now.tv_sec - inode->i_atime.tv_sec) >= 24*60*60)
|
|
return 1;
|
|
/*
|
|
* Good, we can skip the atime update:
|
|
*/
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* touch_atime - update the access time
|
|
* @mnt: mount the inode is accessed on
|
|
* @dentry: dentry accessed
|
|
*
|
|
* Update the accessed time on an inode and mark it for writeback.
|
|
* This function automatically handles read only file systems and media,
|
|
* as well as the "noatime" flag and inode specific "noatime" markers.
|
|
*/
|
|
void touch_atime(struct vfsmount *mnt, struct dentry *dentry)
|
|
{
|
|
struct inode *inode = dentry->d_inode;
|
|
struct timespec now;
|
|
|
|
if (inode->i_flags & S_NOATIME)
|
|
return;
|
|
if (IS_NOATIME(inode))
|
|
return;
|
|
if ((inode->i_sb->s_flags & MS_NODIRATIME) && S_ISDIR(inode->i_mode))
|
|
return;
|
|
|
|
if (mnt->mnt_flags & MNT_NOATIME)
|
|
return;
|
|
if ((mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode))
|
|
return;
|
|
|
|
now = current_fs_time(inode->i_sb);
|
|
|
|
if (!relatime_need_update(mnt, inode, now))
|
|
return;
|
|
|
|
if (timespec_equal(&inode->i_atime, &now))
|
|
return;
|
|
|
|
if (mnt_want_write(mnt))
|
|
return;
|
|
|
|
inode->i_atime = now;
|
|
mark_inode_dirty_sync(inode);
|
|
mnt_drop_write(mnt);
|
|
}
|
|
EXPORT_SYMBOL(touch_atime);
|
|
|
|
/**
|
|
* file_update_time - update mtime and ctime time
|
|
* @file: file accessed
|
|
*
|
|
* Update the mtime and ctime members of an inode and mark the inode
|
|
* for writeback. Note that this function is meant exclusively for
|
|
* usage in the file write path of filesystems, and filesystems may
|
|
* choose to explicitly ignore update via this function with the
|
|
* S_NOCMTIME inode flag, e.g. for network filesystem where these
|
|
* timestamps are handled by the server.
|
|
*/
|
|
|
|
void file_update_time(struct file *file)
|
|
{
|
|
struct inode *inode = file->f_path.dentry->d_inode;
|
|
struct timespec now;
|
|
enum { S_MTIME = 1, S_CTIME = 2, S_VERSION = 4 } sync_it = 0;
|
|
|
|
/* First try to exhaust all avenues to not sync */
|
|
if (IS_NOCMTIME(inode))
|
|
return;
|
|
|
|
now = current_fs_time(inode->i_sb);
|
|
if (!timespec_equal(&inode->i_mtime, &now))
|
|
sync_it = S_MTIME;
|
|
|
|
if (!timespec_equal(&inode->i_ctime, &now))
|
|
sync_it |= S_CTIME;
|
|
|
|
if (IS_I_VERSION(inode))
|
|
sync_it |= S_VERSION;
|
|
|
|
if (!sync_it)
|
|
return;
|
|
|
|
/* Finally allowed to write? Takes lock. */
|
|
if (mnt_want_write_file(file))
|
|
return;
|
|
|
|
/* Only change inode inside the lock region */
|
|
if (sync_it & S_VERSION)
|
|
inode_inc_iversion(inode);
|
|
if (sync_it & S_CTIME)
|
|
inode->i_ctime = now;
|
|
if (sync_it & S_MTIME)
|
|
inode->i_mtime = now;
|
|
mark_inode_dirty_sync(inode);
|
|
mnt_drop_write(file->f_path.mnt);
|
|
}
|
|
EXPORT_SYMBOL(file_update_time);
|
|
|
|
int inode_needs_sync(struct inode *inode)
|
|
{
|
|
if (IS_SYNC(inode))
|
|
return 1;
|
|
if (S_ISDIR(inode->i_mode) && IS_DIRSYNC(inode))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(inode_needs_sync);
|
|
|
|
int inode_wait(void *word)
|
|
{
|
|
schedule();
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(inode_wait);
|
|
|
|
/*
|
|
* If we try to find an inode in the inode hash while it is being
|
|
* deleted, we have to wait until the filesystem completes its
|
|
* deletion before reporting that it isn't found. This function waits
|
|
* until the deletion _might_ have completed. Callers are responsible
|
|
* to recheck inode state.
|
|
*
|
|
* It doesn't matter if I_NEW is not set initially, a call to
|
|
* wake_up_inode() after removing from the hash list will DTRT.
|
|
*
|
|
* This is called with inode_lock held.
|
|
*/
|
|
static void __wait_on_freeing_inode(struct inode *inode)
|
|
{
|
|
wait_queue_head_t *wq;
|
|
DEFINE_WAIT_BIT(wait, &inode->i_state, __I_NEW);
|
|
wq = bit_waitqueue(&inode->i_state, __I_NEW);
|
|
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
|
|
spin_unlock(&inode_lock);
|
|
schedule();
|
|
finish_wait(wq, &wait.wait);
|
|
spin_lock(&inode_lock);
|
|
}
|
|
|
|
static __initdata unsigned long ihash_entries;
|
|
static int __init set_ihash_entries(char *str)
|
|
{
|
|
if (!str)
|
|
return 0;
|
|
ihash_entries = simple_strtoul(str, &str, 0);
|
|
return 1;
|
|
}
|
|
__setup("ihash_entries=", set_ihash_entries);
|
|
|
|
/*
|
|
* Initialize the waitqueues and inode hash table.
|
|
*/
|
|
void __init inode_init_early(void)
|
|
{
|
|
int loop;
|
|
|
|
/* If hashes are distributed across NUMA nodes, defer
|
|
* hash allocation until vmalloc space is available.
|
|
*/
|
|
if (hashdist)
|
|
return;
|
|
|
|
inode_hashtable =
|
|
alloc_large_system_hash("Inode-cache",
|
|
sizeof(struct hlist_head),
|
|
ihash_entries,
|
|
14,
|
|
HASH_EARLY,
|
|
&i_hash_shift,
|
|
&i_hash_mask,
|
|
0);
|
|
|
|
for (loop = 0; loop < (1 << i_hash_shift); loop++)
|
|
INIT_HLIST_HEAD(&inode_hashtable[loop]);
|
|
}
|
|
|
|
void __init inode_init(void)
|
|
{
|
|
int loop;
|
|
|
|
/* inode slab cache */
|
|
inode_cachep = kmem_cache_create("inode_cache",
|
|
sizeof(struct inode),
|
|
0,
|
|
(SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|
|
|
SLAB_MEM_SPREAD),
|
|
init_once);
|
|
register_shrinker(&icache_shrinker);
|
|
|
|
/* Hash may have been set up in inode_init_early */
|
|
if (!hashdist)
|
|
return;
|
|
|
|
inode_hashtable =
|
|
alloc_large_system_hash("Inode-cache",
|
|
sizeof(struct hlist_head),
|
|
ihash_entries,
|
|
14,
|
|
0,
|
|
&i_hash_shift,
|
|
&i_hash_mask,
|
|
0);
|
|
|
|
for (loop = 0; loop < (1 << i_hash_shift); loop++)
|
|
INIT_HLIST_HEAD(&inode_hashtable[loop]);
|
|
}
|
|
|
|
void init_special_inode(struct inode *inode, umode_t mode, dev_t rdev)
|
|
{
|
|
inode->i_mode = mode;
|
|
if (S_ISCHR(mode)) {
|
|
inode->i_fop = &def_chr_fops;
|
|
inode->i_rdev = rdev;
|
|
} else if (S_ISBLK(mode)) {
|
|
inode->i_fop = &def_blk_fops;
|
|
inode->i_rdev = rdev;
|
|
} else if (S_ISFIFO(mode))
|
|
inode->i_fop = &def_fifo_fops;
|
|
else if (S_ISSOCK(mode))
|
|
inode->i_fop = &bad_sock_fops;
|
|
else
|
|
printk(KERN_DEBUG "init_special_inode: bogus i_mode (%o) for"
|
|
" inode %s:%lu\n", mode, inode->i_sb->s_id,
|
|
inode->i_ino);
|
|
}
|
|
EXPORT_SYMBOL(init_special_inode);
|
|
|
|
/**
|
|
* Init uid,gid,mode for new inode according to posix standards
|
|
* @inode: New inode
|
|
* @dir: Directory inode
|
|
* @mode: mode of the new inode
|
|
*/
|
|
void inode_init_owner(struct inode *inode, const struct inode *dir,
|
|
mode_t mode)
|
|
{
|
|
inode->i_uid = current_fsuid();
|
|
if (dir && dir->i_mode & S_ISGID) {
|
|
inode->i_gid = dir->i_gid;
|
|
if (S_ISDIR(mode))
|
|
mode |= S_ISGID;
|
|
} else
|
|
inode->i_gid = current_fsgid();
|
|
inode->i_mode = mode;
|
|
}
|
|
EXPORT_SYMBOL(inode_init_owner);
|